Background: Access to radiotherapy services is critical for effective cancer treatment, yet patients in sub-Saharan Africa face numerous barriers to accessing these services. The region is experiencing a significant increase in cancer cases, with a more than 85% increase in cancer cases reported in the past decade, highlighting the critical role of radiotherapy in enhancing patient prognosis. This systematic review aims to explore the barriers to radiotherapy access in sub-Saharan Africa. The barriers explored will be used to inform the development of the framework to improve access to radiotherapy in the Gauteng provinces, South Africa. Methods: A systematic search of electronic databases was conducted to identify relevant studies published between January 2013 and December 2023. Studies reporting on barriers to radiotherapy access in SSA were included and put into four categories of barriers: health system factors, patient sociodemographic factors, patient factors, and provider factors. Data were synthesised using thematic analysis. Results: This review identifies geographical, financial, cultural, logistical, and systemic barriers to radiotherapy access in sub-Saharan Africa, including limited infrastructure, long travel distances, and inequitable distribution of services. Systemic barriers, including policy gaps and governance issues, also contribute to the inequitable distribution of radiotherapy services in the region. Conclusions: This systematic review highlights the diverse array of barriers to radiotherapy access in sub-Saharan Africa and emphasises the urgent need for targeted interventions to address these challenges.